added 2 recursion questions

Recursion/palindrome-recursion.cpp

@@ -0,0 +1,50 @@
+#include<bits/stdc++.h>
+using namespace std;
+
+class Solution {
+
+  public:
+
+  int sumofDigit(int N){
+
+      int sum=0;
+
+      int temp=N;
+
+      while(temp!=0){
+
+          int x=temp%10;
+
+          sum+=x;
+
+          temp=temp/10;
+
+      }
+
+      return sum;
+
+  }
+
+  int intToString(int N){
+
+      string convertdNum=to_string(N);
+
+      string reverseString=convertdNum;
+
+      reverse(reverseString.begin(),reverseString.end());
+
+      return reverseString==convertdNum ? 1 : 0;
+
+  }
+
+    int isDigitSumPalindrome(int N) {
+
+        // code here
+
+        int ans=sumofDigit(N);
+
+        intToString(ans);
+
+    }
+
+};

Recursion/reverse-stack-recursion.cpp

@@ -0,0 +1,28 @@
+#include<bits/stdc++.h>
+using namespace std;
+
+class Solution{
+public:
+    stack <int> solve(stack <int> &St , stack <int> &answer){
+
+        if(St.empty()){
+
+            return answer ;         
+
+        }
+        int element = St.top() ; 
+
+        answer.push(element) ; 
+
+        St.pop() ; 
+
+        solve(St , answer) ;
+
+        return answer ; 
+    }
+
+    void Reverse(stack<int> &St){
+        stack <int> answer ;
+        St = solve(St , answer) ; 
+    }
+};